Method of treating aluminous materials.



ALDUS G.HIGGINS, OF WORCESTER, MASSACHUSETTS.

METHOD OF TREATING ALUMINOUS MATERIALS.

Specification of Letters Patent.

Patented July 27,1909.

Application filed May 31, 1907. Serial No. 376,567.

To all whom it may concern:

Be it known that I, ALDUs C. HIGGINS, a citizen of the United States,residing at Worcester, in the county of Worcester and State ofMassachusetts, have invented certain new and useful Improvements inMethods of Treating Aluminous Materials, of which the following is aspecification.

The ob'ect of this invention is to prepare a materia suitable for use asan abrasive or for the preparation of grinding or' cutting implements orarticles and for other purposes, by fusing in an electric furnace analuminous material, as for instance anhydrous or hydrated oxid ofaluminum, under such temperature conditions as will yield asubstantially homogeneous and uniform product.

The material produced by the fusion of alumina, raw or calcined bauxiteor other aluminous material, in the electric furnace usually contains asimpurities small proportions of such metals as 'iron, titanium andsilicon, or compounds or oxide of these.

, alloys, carbids or oxids, .which under the variations in t ordinaryconditions of operation, viz., when the material is heated merely to thetemperature of quiet fusion are not uniformly disseminated throughoutthe product but occur therein as more or less segregated -masses, whichare evident in the product is often somewhat irregularly disseminated,

therein, rise to objectionable local e composition or structure of theimplements.

I have now discovered that while the segregation is often marked in theproduct prepared at temperatures not great y exceeding the melting pointof alumina, when thetemperature is carried to a sufliciently high degreesuch segregation either does not occur to any substantial or practicallyobjectionable extent, or if segregation exists at any stage of theoperation it is followed by a distribution or diffusion of the imurities throughout the highly heated and re atively mobile mass; andthat the material produced under such high temperature conditions issubstantially uniform and homogeneous, its value for the preparation ofabrasives being practically unimpaired by the presence of the uniformlydistributed or diffused impurities.

Insufficient temperature conditions in the furnace, with coincident seregation of im all of a number of causes, among which may be mentionedtoo low current density, toorapid feeding of the charge, and thepresence in the char e of an undue proportion of water. Wh' e it is notpracticable to specify a definite suitable temperature in degrees of athermometric scale, such proper temperature' is readily attained andreproduced in practice by observing the above factors and so regulatingthem as to secure the desired results.

The highly heated fused product is in practice permitted to solidify inthe electric furnace, being preferably cooled or chilled therein asdescribed in mycopending application 307,090, filed March 2.0, 1906,whereby a product of exceptional toughness and hardness is produced.

I claim:

1. The method which consists in fusing an aluminous material in anelectric furnace at a temperature substantially above the state of quietfusion and suflicient to prevent substantial segregation of impurities,and. recovering the result'in roduct in solid form.

2. The method whic consists in fusing an aluminous material in anelectric furnace at a temperature substantially above the state of V

